



















































































































































































































































































































































































































































































































































































































































































Class_ 7IZVz£_ 

Book.._ rK 7 K _ 

Cop>Tight N°_'__ 

COPVRIGHT DEPOSIT. 


V 



























































THE KOERTING 

DOUBLE-ACTING TWO-CYCLE 

GAS ENGINE 


THE DE LA VERGNE REFRIGERATING MACHINE CO. 

SOLE LICENSEES FOR THE UNITED STATES 

FOOT OF EAST i ?8th STREET, NEW YORK CITY 

^ ,!»»>»> > >>>,>»»* **»*,* 















J 


.YqS 

, (X 'rJ 




THE LIBRARY OF 
CONGRESS, 
Two Cowes Recsived 

OCT, 18 190? 

Oncvpinwr pnt^v 

Goi.lfy Kjpl- 

CLASS O- XXo. No. 

h^s'/y- 

COPY B. 


Copyright, igoz, by 

The De La Vergne Refrigerating Machine Co. 



Bartlett & Company 
The Orr Press 
New York 



0 











PREFACE 

HE high thermal efficiency of the gas engine has long been recognized, 
but the somewhat clumsy arrangement of the lour-cycle plan, even 
with duplication of cylinders, has never received the hearty endorse¬ 
ment of engineers. 

We are now able to offer a gas engine which differs very little 
in its operation from that of a high-grade steam engine. Having 
the same capacity for regulation, the same flexibility, and running at the same moderate 
speed, it may he expected to have the same durability. 

The Koerting Double-acting Two-cycle Gas Engine, herein described, has been 
pronounced by experts with practical unanimity to be the only one at present meeting 
all the requirements of practice in proper mechanical shape. Additional information, 
prices, etc., may be obtained by application to the sole licensees for the United States, 

THE DE LA VERGNE REFRIGERATING MACHINE CO. 

NEW YORK 

September, 1902 



5 


















THE KOERTING GAS ENGINE. Built by THE DE LA VERGNE 
REFRIGERATING MACHINE CO., NEW YORK. Sole Licensees for the U.S.A. 


HE discovery of the fact that gases of low heating capacity could be used effectively 
in gas engines has created a demand for one of higher grade than was previously 
called for. This demand for high-class engines was more pronounced in Europe than 
in this country for the reason that the relative cheapness of steam coal here prevented 
the general introduction of gas-producer plants. 

An immense impetus to the construction of larger gas engines was given hy the 
comparatively recent discovery that the gases given off by blast furnaces could he utilized in gas engines, 
and the demand for units of 1000 horse-power, 2000 horse-power and upwards, compelled a reconsider¬ 
ation of the design of the gas engine. 

The four-cycle plan is the one generallv adopted for engines of small power, because then the same 
piston and cylinder can he used as pump for sucking and preparing of the charge, and as power cylinder. 
Engines of great power, however, become very large and heavy, in fact the limit in size for building 
such single-cylinder engines is soon arrived at. Hence large engines have usually been built with 
several cylinders rather than with a cylinder of too great dimensions. The result was the so-called 
“ tandem,” “ twin,” and three and four-cylinder engines. Engines of these types can only be con¬ 
sidered as a makeshift, as they are very complicated, and therefore more liable to get out of order. 

In large four-cycle engines the valve boxes also present great difficulties in construction, owing to 
the immense valves, especially the exhaust valves, often resulting in failures. In consequence of all 
these considerations, many attempts have been made to design large gas engines on a different plan. 



7 









THE DE LA VERGNE REFRIGERATING MACHINE CO., NEW YORK. 









SIDE ELEVATION OF THE KOERTING ENGINE 

8 














































































THE DE LA VERGNE REFRIGERATING MACHINE CO., NEW YORK 


Mr. Ernst Koerting was peculiarly fitted to attack this problem. He is universally acknowledged 
to be an expert on all questions relating to the gas engine, and he started, therefore, with a full knowl¬ 
edge of the requirements of the case (his firm having built many thousand gas engines), and moreover 
with a practical acquaintance (which only long experience could give), with all the advantages and 
disadvantages of various possible constructions. 

The Koerting Double-acting Two-cycle Gas Engine is the result of tests and experiments extending 
over a period of almost five years, conducted on models and on a 400-horse-power gas engine built in the 
Koerting shops. It was found that the new system complied fully with all the requirements. There¬ 
upon they commenced to build these engines and they proved an immediate and complete success. 

The method of operation of Koerting’s Double-acting Two-cycle Gas Engine is as follows: 

The engine is double-acting like a steam engine, hence the crank end and the head end of the 
power cylinder are similar, the admission valves are located in the valve boxes, which are bolted to the 
cylinder heads. There are no exhaust valves required, as the products of combustion escape through 
slots or ports cast in the middle of the cylinder from where the exhaust pipe leads. These slots are 
covered by the motor piston itself. For this purpose the piston is made very long and is packed at 
each end by the customary self-closing spring rings. 

The combustible mixture is admitted through two double-acting auxiliary pumps, the one for gas, 
the other for air. These pumps are so proportioned that their combined action always secures the 
proper mixture necessary for perfect combustion and introduces the same to the working cylinder. The 
compression spaces of the pumps are divided, so that the crank ends of the air pump and gas pump 
discharge into the crank end of the power cylinder, and the head ends of the pumps discharge into the 


9 




THE DE LA VERGNE REFRIGERATING MACHINE. CO., NEW YORK 


















































THE DE LA VERGNE REFRIGERATING MACHINE CO., NEW YORK 


head end of the power cylinder. By the pumps the gas and air are compressed to about nine pounds 
per square inch. 

Referring to the drawing on opposite page, it will he seen that the piston is at the outer dead point, 
and that the exhaust ports are exposed toward the opposite or head end of the engine. The instant the 
piston begins to uncover the exhaust ports, the pressure of the residual products of combustion in the 
cylinder drops rapidly to that of the atmosphere ; when this has taken place, the inlet valve is opened 
and a fresh charge admitted by the pumps. The valve gear of these is so designed that air only is 
supplied first, to separate the burnt gases from the succeeding mixture and afterwards gas and air, mixed 
in proper proportions. (See also page 20). 

The combustible mixture of gas and air is produced only at the inlet to the cylinder (see page 14). 
There is no storing of it, and this represents a very considerable advantage over engines that keep more 
or less of the combustible mixture outside of the working cylinder. By suitable construction of the 
admission device, mingling of the air first introduced with the burnt residue gases, or with the succeed¬ 
ing charge of the combustible mixture, is adequately avoided. For the same reason, loss of mixture 
through the exhaust ports, which are open during this period, is effectively prevented. 

Shortly after the exhaust ports are again covered by the receding piston, the air and gas pump 
pistons arrive also at their dead point position, and the supply of mixture is interrupted. The inlet 
valve closes and the charge is compressed in the cylinder in the usual method, till, at the dead point of 
the stroke, ignition takes place. 

At the next movement of the main piston, the ignited charge exerts its driving power by expand¬ 
ing till just before arriving at the other dead points, when the piston uncovers the exhaust ports again 




THE DE LA VERGNE REFRIGERATING MACHINE CO., NEW YORK 



SIDE ELEVATION OF THE 
K.OERTING ENGINE SHOW¬ 
ING FOUNDATION 



































































































THE DE LA VERGNE REFRIGERATING MACHINE CO., NEW YORK 


and allows the consumed charge to be blown out. On the opposite end of the piston the same operation 
takes place. 

In order to secure the separating layer of air above referred to, between the hot consumed gases 
and the fresh charge, the gas pump is so constructed that no gas is delivered until after a certain point 
in its compression stroke. The pump is provided with piston valves with the valve gear so arranged 
that its maximum capacity cannot exceed 50 to 60 per cent, of its total displacement. For after 
the pump has completed the suction stroke, the gas suction port is left open during a portion of 
the succeeding (compression) stroke, so that the gas can return without increase in pressure until the 
suction port is closed, when the gas is compressed and passed out through the compression port. 

The amount of gas thus furnished corresponds to the maximum power of the engine. 

Regulation of the power is effected as follows : When the load on the engine is reduced, the gas 
pump begins to furnish gas at a correspondingly later period, thus discharging a diminished quantity of 
gas into the working cylinder. This is accomplished either by the valve gear of the pump and con¬ 
trolled by the governor, or by a by-pass located between each pump end and respective compression 
channel which leads to the inlet valve on the main cylinder. The throttling device in this by-pass is 
also under the control of the governor. 

It is evident from the above, that the engine operates with a variable amount of mixture, and that 
correspondingly more or less air is sent first into the power cylinder. This air stays near the middle of 
the cylinder, while the combustible mixture remains at the heads of the cylinder near the inlet valves 
and igniters. The peculiar shape of the cylinder heads prevents mingling of the layer of air with the 
following mixture of gas and air. 


13 




THE DE LA VERGNE REFRIGERATING MACHINE CO., NEW YORK 



SECTION THROUGH SUCTION 
VALVE OF THE KOERTING 
ENGINE 






■gift, 


<-rrr S'/,.*.; 





















THE DE LA VERGNE REFRIGERATING MACHINE CO., NEW YORK 


For ignition there are provided two spark coils at each end ot the power cylinder. These are 
operated by a separate shaft, driven by spur gearing from the cam shaft. The gear on the igniter shaft 
is not fast, it is connected with a sleeve having a feather, which is set spirally around the shaft so that 
by a sliding movement of the wheel the igniter shaft may be set behind or in advance of the cam shaft. 
Thus the time of ignition can he changed during running of the engine to suit whatever kind of gas is 
being used. A further advantage secured by this arrangement is, that at starting, the point of ignition 
may be so set that ignition takes place only after the piston has passed the dead point, and the engine 
started very slowly without incurring any pre-ignition. Very lean gases require much earlier ignition 
than is otherwise usual. In practice, indicator cards are taken from time to time to check the timing 
of the ignition, and to see whether the combustion of the gases is without fault. Igniting ot very poor 
gas mixtures presents no difficulties at all with this arrangement. 

The engine is started with compressed air. Engines to which a blowing cylinder is attached are 
easily started with air under i 50 pounds pressure, for those without such cylinders 90 to 1 20 pounds 
per square inch is sufficient. 

This circumstance is of greatest importance, as this air pressure does not exceed the amount of 
compression under which the engine runs, namely, 150 to 175 pounds. For no compressed air 
can enter near the dead point position where compression of the mixture is at maximum, and so the 
ignition can take place without being unfavorably influenced bv such air, which is thus automatically 
cut out. 

A piston valve is provided for admitting the compressed air at front and back ends of the cylinder, 
as in a slide-valve steam engine. This piston valve is operated from the cam shaft by an eccentric, 


1 5 




THE DE LA VERGNE REFRIGERATING MACHINE CO., NEW YORK 



THE KOERTING ENGINE WITH BLOWER IN TANDEM 


6 























THE DE LA VERGNE REFRIGERATING MACHINE CO., NEW YORK 


which can be thrown in or out of gear like a clutch. Filling the cylinder with air twice is generally 
sufficient for starting up, after which the engine runs itself. No existing type of engine can be started 
with equal certainty and rapidity. 

The power cylinder and piston are cooled by circulating water, which in the case of the piston 
enters the tube carried through the crosshead pin and hollow piston rod, and returns the same way, but 
on the outside of the tube. The stuffing boxes in the cylinder heads are surrounded by water. The 
cylinder walls also are cooled throughout except at the middle where the exhaust slots are. 

Investigations of the heating-up of the main cylinder walls have shown that such is within 
moderate limits, so that the durability of the cylinder is permanently insured ; the average temperature 
of the walls is lower than in the case of a high-pressure steam engine. 

By maintaining the piston cooler than the cylinder, the expansion of the former is under entire 
control and the result is good running of the engine. 

The cylinder is equipped with relief valves which serve also as safety valves. Hand-hole plates are 
provided for cleaning the exhaust ports. Experience has shown, however, that the inside of the cylinder 
remains very clean. It was found that even after long continuous running the exhaust ports especially 
remained perfectly clean, which is the result of the violent discharge of the burnt gases occurring alter- 
natelv from right and left. This is an important point, for in other engines where the gases are always 
blown out in the same direction, scale or crusts of oil form, which become intensely hot and are 
therefore very apt to cause premature ignition. Formation of the oil crusts is further effectively pre¬ 
vented by the cool piston sliding over the bridges that separate the exhaust ports, thus keeping the 
temperature of these so low that the adhering lubricating oil does not vaporize. 






THE DE LA VERGNE REFRIGER¬ 
ATING MACHINE CO., NEW YORK 





























































































































THE DE LA VERGNE REFRIGERATING MACHINE CO., NEW YORK. 


IE cut on the opposite page indicates one favorite 
combination of the Koerting engine, namely, di¬ 
rectly connected with an electric generator. In the 
case of alternating; currents the revolving- held can 
be arranged to answer the purpose of a fly-wheel. 
The cut on page 16 shows another combina¬ 
tion of a Koerting engine driving a horizontal blower in tandem. We 
also build this engine in combination with vertical blowers. The frame 
of the blower being astride of the engine frame and its connecting 
rod driven from the same crank-pin, with or without additional 
engine as on page 18. 



*9 









THE DE LA VERGNE REFRIGERATING MACHINE CO., NEW YORK 




Combustible Mixture 


Air 


Burned Gases 


SUCCESSION OF CHARGES IN THE KOERTING ENGINE 





















THE DE LA VERGNE REFRIGERATING MACHINE CO., NEW YORK 


HE diagram on the opposite page illustrates the succession of charges in the power 
cylinder of the Koerting engine. In the upper figure, representing normal con¬ 
ditions, it will he seen that the burnt products have passed through the exhaust 
port and have been followed by a portion of the pure air, which thus operates 
as a scavenging charge. The layer of pure air is succeeded by a layer of mixture 
of constant proportions, in so far as intermixture with the layer of air is prevented. 

In the second figure this wad of air is longer and the succeeding wad of mixture is shorter. 
The mixture, however, remains near the ignition end of the cylinder and maintains substantially the 
proper proportions for easy ignition. 

The third figure illustrated the means of obtaining an overload. In this case the wad of 
air is shortened and the wad of mixture lengthened beyond their normal length. This overload 
involves the risk of a small loss of the mixture through the port, and is intended to he used 
temporarily only. It is a distinctive and very valuable characteristic of the Koerting engine. 







THE DE LA VERGNE REFRIGERATING MACHINE CO., NEW YORK 

Koerting Gas Engine 


Caloric Engine 

y - I Direct-acting Steam Pump 
Slide-valve Engine 

Simple Corliss, non-condensing 


Simple Corliss, condensing 

Steam I urbme 


Compound Engine (Sulzer) 

| Compound (McIntosh & Seymour) 


Triple Expansion (Reynolds) 

Triple Expansion (Leavitt) 
Quadruple Expansion (Nordberg) 



Koerting Gas Engine 


RELATIVE THERMAL EFFICIENCY OF VARIOUS ENGINES 


















THE DE LA VERGNE REFRIGERATING MACHINE CO., NEW YORK 


HE diagrams on the opposite page show in a 
very impressive manner the superior thermal effi¬ 
ciency of the Koerting gas engine as compared 
with even the very highest development in steam 
engineering. 

Professor E. Meyer has experimentally deter¬ 
mined a thermal efficiency tor the Koerting Double-acting Two- 
cycle Engine of 38 per cent. 

It is with extreme difficulty that the thermal efficiency of a 
multiple-cylinder steam engine can he made to exceed 22 per cent. 

It would seem, therefore, that the future of the gas engine 
is fully assured. 



2 3 





AGGREGATE AMOUNT OF KOERTING GAS ENGINES SOLD BY US IN THE 
UNITED STATES TO DATE REPRESENTS 

41,800 HORSE-POWER 

ft 

1 

FOR FURTHER INFORMATION AND ESTIMATES ON ANY SIZE ENGINES 
FROM 400 TO 2000 HORSE-POWER, APPLY TO 

THE DE LA VERGNE REFRIGERATING MACHINE CO. 

FOOT EAST 1 38 th STREET, NEW YORK CITY 

SOLE LICENSEES FOR THE UNITED STATES 


2 4 












